The Austin Flint Murmur



Fig. 12.1
Graphical representation of auscultation findings in a patient with the Austin Flint murmur








    Test Results






    • Color M-mode and 2-D echo (Fig. 12.2a–d).

      A310603_1_En_12_Fig2a_HTML.gifA310603_1_En_12_Fig2b_HTML.gif


      Fig. 12.2
      (a–d) Echocardiograms. (a) An abnormal valve with deformed left coronary leaflet. (b) Severe aortic regurgitation on color Doppler. (c) The AR jet courses along the anterior mitral leaflet. (d) Fluttering and early closure of the mitral valve is shown on M-mode




      • Backflow evident in thoracic aorta, demonstrating severe regurgitation.


      • Anterior mitral valve leaflet (AMVL) flutters due to turbulent flow impinging on mitral valve in proto-diastole, mid-diastole and during atrial contraction [1].



    Clinical Basics



    Normal Anatomy






    • Normal anatomy of the aortic valve can be reviewed in chapters on aortic stenosis and aortic regurgitation.


    Definitions






    • Though the Austin Flint murmur presents like a mitral murmur, it does not indicate the presence of any mitral valve lesions. Rather, AF accompanies severe aortic lesions coupled with considerable AR.


    Etiology






    • The etiology behind AF is not completely understood. However, it is agreed that AF is NOT due to functional MS.


    • Some commonly accepted mechanisms for AF include:



      • Functional mitral stenosis during ventricular filling. This results from the regurgitant AR jet impinging on the AMVL and restricting atrial-ventricular flow [1].


      • The aortic valve stream contacts the mitral valve stream, with the AMVL vibrating between them. This causes turbulence in the apical area [1].


      • Turbulence caused by the apical irradiation of the regurgitant aortic jet could cause the murmur [1].


      • The regurgitant jet’s impact on the left ventricular imaging studies suggests a combined etiology including turbulent flow, mitral valve fluttering, and septal bulging [1].


    • The direction of AR flow seems unrelated to the presence of AF.


    • While AF is correlated with increased peak mitral inflow velocity there is no temporal relationship between AF and mitral flow (phonocardiography).


    Presentation






    • Patients with an AF murmur may be asymptomatic or present with progressive exertional dyspnea [2].


    • A large-volume collapsing pulse is likely present due to the severity of aortic regurgitation [2].


    Prevalence






    • One study found that out of 51 patients with AR and a normal MV, 30 exhibited findings suggestive of the AF murmur.
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    Related posts:

    1. Aortic Sclerosis
    2. Pulmonic Valve: Pulmonic Regurgitation
    3. Aortic Stenosis
    4. Mitral Stenosis

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    Jul 10, 2016 | Posted by in CARDIOLOGY | Comments Off on The Austin Flint Murmur

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